Q&A: Introducing GBD 2021

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This transcript has been lightly edited for clarity

Why is the Global Burden of Disease important, what does it do, and who uses it?

The Global Burden of Disease, which has been running for over 30 years, is the one way that the world can have comparable measurement of every major disease, injury, and risk factor for countries over time. It is a huge effort at systematizing the information on health around the world.

And in fact, because it’s been around for a long time and it is the only comparable source that’s out there, it’s used by nearly every government and it’s widely used by the scientific community. It’s used by NGOs [non-governmental organizations]. It’s really used by everybody who is interested in benchmarking their population against itself over time or against other comparable communities around the world.

What is the significance of the new version of the Global Burden of Disease study currently being rolled out?

GBD 2021, which has estimates from 1990 to 2021 for every outcome and goes all the way back to 1950 for some outcomes like age-specific mortality or fertility, is now rolling out to the world. It’s taken longer for us to produce the GBD than normally, and that’s because of the complexity of COVID.

So what’s new in the new study is the usual update of new data that’s come in, new understanding for certain risk factors. But fundamentally, it’s about what does all the data tell us with a little bit of hindsight about what happened during the COVID pandemic, and how does that change the broader trends that we’ve been watching over the last three decades around the world?

How is the new iteration of the GBD related to the COVID pandemic?

In the period from 1990 to 2019, there are some big, broad, dramatic trends in the world, like the HIV epidemic unfolding in Eastern and Southern Africa, or the rise of adult mortality in Eastern Europe and Central Asia. 

But COVID came along and had this acute crisis. It raised mortality dramatically in a number of places, particularly in older age groups. In some parts of the world, for example, Peru or Bolivia or Ecuador, or parts of Mexico, there were huge increases in mortality, and in other places, not much in the way of increases of mortality – think Australia or New Zealand. 

And so you had this huge range of outcomes related to COVID. And unlike the previous 30 years, where changes were sort of incremental, these dramatic changes in COVID and very heterogeneous changes have meant that we’ve needed a lot more new and updated data. That takes a while to come in to try to tease apart what actually happened: Where were the effects big? Where were the effects much smaller? 

We saw during COVID adjacent countries with very different outcomes. And that has to do with vaccination. It has to do with efforts to curtail transmission through a variety of policies and individual behaviors and some factors that we don’t really fully understand. 

And so it’s been an incredible effort to try to figure out what all that data means and build it in to the standardized calculations and estimation processes of the GBD. And that’s now what we have available, at least for the first two years of the pandemic through 2021.